If a - b = 1 and a + b = 3, the value of ab is: 1. 4 2. 2 3. -2 4. 0

Question

KnowledgeBoat · Accepted Answer

Using the formula, [∵(x \+ y)² = x² \+ 2xy \+ y²] And [∵(x \- y)² = x² \- 2xy \+ y²] (a \+ b)² = a² \+ 2ab \+ b² Putting a \+ b = 3, we get (3)² = a² \+ 2ab \+ b² 9 = a² \+ 2ab \+ b² 9 \- 2ab = a² \+ b² ...............(1) And, (a \- b)² = a² \- 2ab \+ b² Putting the value, a \- b = 1 (1)² = a² \- 2ab \+ b² 1 = a² \+ b² \- 2ab Using equation (1) 1 = 9 \- 2ab \- 2ab 1 = 9 \- 4ab 4ab = 9 \- 1 4ab = 8 ab = ab = 2 Hence, option 2 is the correct option.

Mathematics

If a - b = 1 and a + b = 3, the value of ab is:
4
2
-2
0

Identities

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If a + b = 5 and ab = 6, find a² + b²

Mathematics

If a - b = 1 and a + b = 3, the value of ab is:42-20

Identities

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If a - b = 1 and a + b = 3, the value of ab is:
4
2
-2
0

If a + b = 7 and ab = 10; the value of a² + b² is equal to:
29
49
39
69

If a + b = 5 and ab = 6, find a² + b²